Purpose: To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting: Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano-Milan, Italy. Methods: This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with -2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, optical refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results: At 1 year, the mean BSCVA was 0.6 ± 0.72 with -2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with -2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions: After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the optical refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.
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